Greg KH, Linux kernel developer delivered a keynote in the Linux plumbing conference about the health of the ecosystem. His message was essentially that distributions that don't contribute to the ecosystem have to rely on the whims of others which is unhealthy for them. Here is an introduction the development model and some interesting statistics about the Linux kernel code. Update by TH: Rebuttals are appearing all over the web, like this one by Canonical's Matt Zimmerman ("He's refuting a claim which has, quite simply, never been made. [...] When this sort of thing happens on mailing lists, it's called trolling."), or this one by another Canonical employee, Dustin Kirkland.

Shouldn't open source and free software be about cooperation more than about small camps (or big corporations) fighting each other?

Canonical concentrates especially on the desktop level development instead of kernel level work. Big deal? Isn't concentration good? Somebody is good at something and concentrates on that and it will benefit the whole open source community - because the source code is open and free to to use.

People, like the Ubuntu developers (most are or were Debian developers too), were happy with Debian but there was need to improve its usability, especially on the desktop level. That - desktop usability - was and still is the main focus of Ubuntu and Canonical, not kernel development.

So maybe Canonical could try to contribute a bit more to kernel development too, by sending patches etc. Let's hope they will find more resources even to that too. Although many people already accuse Ubuntu and Canonical of focusing on all too many things simultaneously...

But Canonical is not a big rich corporation. Mark Shuttleworth - as rich as he may be compared to most people - doesn't have endless amounts of money to throw around. Most developers hired by Canonical have been desktop developers.